Electric actuator for a marine steering system, and methods of defining steering boundaries and determining drive mechanism failure thereof

Abstract

An electric actuator for a marine steering system comprises a housing and an output shaft reciprocatingly received by the housing. There is a rotor disposed within the housing. The rotor is coupled to the output shaft of the electric actuator. Rotation of the rotor causing the output shaft of the electric actuator to reciprocate relative to the housing. There is a motor disposed within the housing. The motor has an output shaft coupled to the rotor. A longitudinal axis of the output shaft of the motor is parallel with a longitudinal axis of the output shaft of the electric actuator. There is also a drive mechanism disposed within the housing. The drive mechanism couples the output shaft of electric actuator to the rotor. The drive mechanism is on a plane radial to a longitudinal axis of the output shaft of the motor. There is an actuator position sensor disposed on the rotor for sensing a position of the rotor. The actuator position sensor senses an actual steering position based on a position of the rotor. There is a motor position sensor disposed on the output shaft of the motor for sensing a rotating position of the motor. The motor position sensor senses a relative steering position based on a position of the motor.

What is claimed is: 
     
       1. A method of defining an actuator steering boundary on a marine vessel, the method comprising:
 determining if a sensor of a first actuator of a first propulsion unit of the marine vessel has failed; and 
 if so, using a last known position of the first said actuator to define a steering boundary of allowable steering of a second actuator of a second propulsion unit of the marine vessel to inhibit propulsion unit collision. 
 
     
     
       2. The method as claimed in  claim 1  wherein the second said actuator is adjacent to the first said actuator. 
     
     
       3. The method as claimed in  claim 1  further including after determining that the sensor of the first said actuator has failed:
 if the second said actuator is between the first said actuator and a third said actuator of a third said propulsion unit of the marine vessel, using positioning of the third said actuator to further define the steering boundary of allowable steering of the second said actuator. 
 
     
     
       4. The method as claimed in  claim 3  further including:
 using positioning of the second said actuator to define a steering boundary of allowable steering of the third said actuator. 
 
     
     
       5. The method as claimed in  claim 1  further including within determining that the sensor of the first said actuator has failed:
 if a third said actuator of a third said propulsion unit of the marine vessel is adjacent to the first said actuator, using the last known position of the first said actuator to define a steering boundary of allowable steering of the third said actuator. 
 
     
     
       6. A method of defining a steering boundary of an actuator of a first propulsion unit mounted on a marine vessel, the marine vessel including at least one of a second propulsion unit having an actuator and a third propulsion unit having an actuator, the method comprising:
 determining if a sensor of the actuator of a first of the second propulsion unit and the third propulsion unit has failed; and 
 if so, using a last known position of the actuator of the first of the second propulsion unit and the third propulsion unit to define a steering boundary of allowable steering of the actuator of the first propulsion unit to avoid propulsion unit collision. 
 
     
     
       7. The method as claimed in  claim 6 , further comprising:
 determining if a sensor of the actuator of a second of the second propulsion unit and the third propulsion unit has failed; and 
 if so, using a last known position of the actuator of the second propulsion unit and the third propulsion unit to further define the steering boundary of allowable steering of the actuator of the first propulsion unit to avoid propulsion unit collision if the first propulsion unit is between the second propulsion unit and the third propulsion unit. 
 
     
     
       8. A method of defining one or more steering boundaries of one or more actuators on a marine vessel, the marine vessel including a plurality of propulsion units with each said propulsion unit having a respective said actuator, the method comprising:
 determining if a sensor of one said actuator has failed; and 
 if so, using a last known position of the one said actuator to define one or more steering boundaries of allowable steering of one or more other said actuators to inhibit propulsion unit collision. 
 
     
     
       9. The method as claimed in  claim 8  wherein the one or more other said actuators comprise one or more said actuators which are adjacent to the one said actuator that has failed. 
     
     
       10. The method as claimed in  claim 8  wherein the one said actuator having the failed sensor comprises the actuator of a first of a port said propulsion unit and a starboard said propulsion unit, and the one or more other said actuators comprise the actuator of at least one said propulsion unit between the port said propulsion unit and the starboard said propulsion unit. 
     
     
       11. The method as claimed in  claim 8  wherein the one said actuator having the failed sensor comprises the actuator of a first of a port said propulsion unit and a starboard said propulsion unit, and the one or more other said actuators comprise the actuator of a second of the port said propulsion unit and the starboard said propulsion unit. 
     
     
       12. The method as claimed in  claim 11  wherein the one or more other said actuators further comprise the actuator of at least one said propulsion unit between the port said propulsion unit and the starboard said propulsion unit. 
     
     
       13. A method of maintaining steering ability and inhibiting propulsion unit collision for a marine vessel, the marine vessel including a plurality of propulsion units with each said propulsion unit having a respective actuator, and the method comprising:
 determining if a sensor of one said actuator has failed; 
 if so, using a last known position of the one said actuator to define a steering boundary of allowable steering of one or more other said actuators to inhibit propulsion unit collision; and 
 using the one or more said propulsion units of the one or more other said actuators to maintain steering ability of the vessel. 
 
     
     
       14. The method as claimed in  claim 13  wherein the one or more other said actuators comprise one or more said actuators which are adjacent to the one said actuator that has failed. 
     
     
       15. The method as claimed in  claim 1 , further including:
 providing each said actuator with a position said sensor thereon to determine positioning thereof. 
 
     
     
       16. The method as claimed in  claim 1 , wherein said sensor comprises an actuator position sensor, wherein each said actuator includes an output shaft, and the method further including:
 providing each said actuator with its actuator position sensor along a longitudinal axis of the output shaft thereof, each said actuator position sensor sensing an actual steering position. 
 
     
     
       17. The method as claimed in  claim 1 , wherein said sensor comprises a motor position sensor, wherein each said actuator includes a motor having an output shaft, and the method further including:
 providing each said actuator with its motor position sensor along the output shaft of the motor thereof, the motor position sensor sensing a relative steering position based on a position of the motor. 
 
     
     
       18. A method of improving steering when a sensor of an actuator of a first of a plurality of propulsion units of the marine vessel has failed, the method comprising:
 determining whether a drive mechanism of the actuator of the first said propulsion unit has failed; 
 if no, determining whether the actuator of a second said propulsion unit has a functional sensor; 
 if yes, repositioning the first said propulsion unit with the failed sensor to promote an improved steering range for the actuator of the second said propulsion unit. 
 
     
     
       19. The method as claimed in  claim 18 , the method further including:
 determining that the drive mechanism of the actuator of the first said propulsion unit has failed by comparing an actuator position sensor signal of the actuator of the first said propulsion unit with a motor position signal of a motor of the actuator of the first said propulsion unit. 
 
     
     
       20. The method as claimed in  claim 18 , wherein each said actuator includes a controller, and the method includes:
 each said controller continuously communicating an actuator sensor position thereof as well as sensor and self-diagnostic status information to other said controllers. 
 
     
     
       21. The method as claimed in  claim 20 , wherein each said controller communicates to the other said controllers via a CAN bus network. 
     
     
       22. The method as claimed in  claim 18 , further including:
 determining the steering range of each said actuator based on sensor position and self-diagnostic statuses communicated by the other said controllers. 
 
     
     
       23. A method of detecting drive mechanism failure in an electric actuator of a propulsion unit for a marine vessel, the method including:
 providing the electric actuator with a rotor, wherein rotation of the rotor causes an output shaft of the electric actuator to reciprocate; 
 providing the electric actuator with a motor having an output shaft, wherein a longitudinal axis of the output shaft of the electric actuator is parallel with a longitudinal axis of the output shaft of the motor; 
 providing the electric actuator with a drive mechanism coupling the output shaft of the motor to the rotor; 
 providing the electric actuator with an actuator position sensor along the longitudinal axis of the output shaft of the electric actuator, the actuator position sensor sensing an actual steering position; 
 providing the electric actuator with a motor position sensor along the output shaft of the motor, the motor position sensor sensing a relative steering position based on a rotating position of the motor; and 
 comparing an actuator position sensor signal and a motor position signal to determine drive mechanism failure. 
 
     
     
       24. The method according to  claim 23  further including providing motorized repositioning of the electric actuator when drive failure mechanism is determined. 
     
     
       25. The method according to  claim 23  further including providing manual repositioning of the electric actuator when drive failure mechanism is determined. 
     
     
       26. A method of detecting drive mechanism failure in an electric actuator of a propulsion unit for a marine vessel, the electric actuator including an output shaft, a rotor rotation thereof causing the output shaft to reciprocate, a motor with an output shaft, and a drive mechanism coupling the output shaft of the motor to the rotor, the method including:
 providing an actuator position sensor along the output shaft of the electric actuator, the actuator position sensor sensing an actual steering position; 
 providing a motor position sensor along the output shaft of the motor, the motor position sensor sensing a relative steering position based on a rotating position of the motor; and 
 comparing an actuator position sensor signal and a motor position signal to determine drive mechanism failure. 
 
     
     
       27. The method as claimed in  claim 26 , wherein the actuator position sensor is positioned along a longitudinal axis of the output shaft of the electric actuator. 
     
     
       28. The method as claimed in  claim 25 , the method including:
 determining that drive mechanism failure has occurred if the actuator position sensor signal remains stationary while the motor position sensor signal is changing in rate and direction as the motor rotates.